1. Field of the Invention
This invention relates to the art of sail construction, and more particularly concerns a sail having a multiplicity of adjoining pockets arranged in a honeycomb array to increase the effective wind catchment efficiency and to maximize stability of lift of the sail.
2. Description of the Prior Art
In U.S. Pat. No. 2,159,923 there is described a sail having a multiplicity of semi-ellipsoidal pockets. Each pocket is oriented on an axis disposed at an angle to the straight bottom foot of the sail. The pockets are spaced apart, with no pocket edges contiguous. Each pocket has a shallow lower end and deeper upper end. This arrangement of pockets is said to impart a lifting effect when driving wind impinges on the sail.
In U.S. Pat. No. 3,851,612 there is described a spinnaker, the lower portion of which has a plurality of rectangular pockets aligned horizontally and vertically. These pockets are scoop shaped with shallow inner ends disposed closer to the center vertical line of the sail and deeper outer ends disposed further from the center line of the sail. The pockets are said to serve aerodynamic lifting and stabilizing functions, and are also said to help keep the sail open to the wind.
The pockets in the prior sails cover only relatively small portions of the wind impingement area, so that they produce limited beneficial aerodynamic effects. The horizontal, vertical, or inclined orientation of the pockets produces destabilizing effects unless the wind impinges head on. Since the wind shifts constantly it rarely inpinges head on for more than a few moments at a time. At all other times the presence of the pockets causes destabilization effects regardless of the particular orientation of the axes of the pockets.